Project Summary/Abstract Adolescent and young adult (AYA) survivors of pediatric cancers require lifelong ?risk-based? follow-up care tailored to their treatment exposures, including routine medical appointments, monitoring for late effects, and regular cancer screenings. In addition to normal developmental tasks of pursuing higher education, initiating careers, living independently, and forming intimate relationships, AYA survivors must also assume primary responsibility for the management of their long-term follow-up care. This transition from parent-guided management to self-management of medical care can be challenging for the AYA and his or her family, resulting in lapses in care and potentially preventable health problems. Only a minority of young adult cancer survivors obtain risk-based follow-up care; one major contributor to non-adherence is a lack of preparation or low ?transition readiness? to transfer to adult-oriented care. The goal of this project is to pilot test a self-management + peer mentoring intervention to improve AYA cancer survivor transition readiness. Based on the Social-Ecological Model of AYA Readiness for Transition and interviews with AYA cancer survivors, parents, and providers, we created the content for the self- management intervention that focuses on overcoming survivor barriers to self-management such as lack of knowledge, low self-efficacy, and poor communication skills. Peer mentors are a novel component of the intervention and serve to provide credible specialized information, empathy, and advice, capitalizing on shared experience and meeting a psychosocial need for AYA survivors. We conducted a small pilot with AYA survivors to gain feedback on the content and infrastructure of the peer mentor component. AYA survivors found the content, online delivery, and peer mentor contact acceptable, but highlighted a need for engaging online tools. This project will utilize AYA survivor input to build the online intervention with interactive tools such as personalized feedback, animated videos, and games to encourage engagement with the intervention. Then we will conduct a randomized pilot test of the intervention to evaluate feasibility, acceptance, and preliminary effects on AYA transition readiness.